There is an issue problems to unlock those achievements. For Example, when I got double flawless victory on stage 9 (Third battle of 2 opponents), it not unlock. I found out the problem is when you lose a match, the achievements are void. The achievements

18 May
16:13 2014

The achievements for beating the game each characters, it unlock after you defeat Goro instead of defeat Shung Tsung without losing the match. All the achievements need to recheck for improve and fix.

It's easier to get flawless with Goro. First end the game and when THE END stops in the middle of the screen, hold up + left + select + A till enter initials screen or start credits screen, then push start.